1. Field of the Invention
This invention relates to liquid flow systems and in particular to such systems utilizing means for effecting a swirling movement to the liquid being flowed through a flow passage such as for use in effecting a centrifugal solid separation operation.
2. Description of the Prior Art
In one improved form of dishwashing liquid flow system, a portion of the dishwashing liquid being delivered to the circulation pump is bypassed to a soil separator by a centrifugal bypass flow operation. To effect such centrifugal operation, it is necessary to impart a swirling movement to the dishwashing liquid being flowed through a flow passage of the separator leading to the circulation pump. While the pump effects a longitudinal flow of dishwashing liquid through the flow passage, separate means must be provided to effect the desired swirling movement. The present invention is concerned with an improved means for effecting the desired swirling movement in such a liquid flow system.
The use of a screen for separating particles at the inlet to a fluid flow system is shown in U.S. Pat. No. 1,762,028 of Morton F. Phelps. As shown therein, the exhaust fan shaft is provided with a perforated disc, or screen member, which rotates with the blast wheel and functions to separate solid matter from the air drawn through the inlet opening so as to prevent that solid matter from contacting the blast wheel blades.
Roy N. Anderson shows, in U.S. Pat. No. 3,096,718, a trash cutter for a pump arranged to chop up foreign matter before it enters the interior of the pump so as to prevent clogging of the pump. The shearing of foreign matter is effected by a cutting element attached to the pump body adjacent the blades of the pump so that the pump blades themselves function as a portion of the cutting means.
Phil H. Griffin, III shows an overload controlled drilling mud treatment system in U.S. Pat. No. 3,214,019, wherein jamming of an intake screen by foreign matter causes disengagement of the pump from its power source. The pump water, however, is continued to be supplied to the discharge outlet of the screen housing for flushing purposes.
J. E. Bowden et al, in U.S. Pat. No. 3,271,929, show a reconditioner for used drilling mud utilizing rotating perforated cone discs for desanding and degassing the used drilling mud.
A pump for a dishwasher is shown in U.S. Pat. No. 3,434,671 of Donald S. Cushing et al, which pump is provided with a macerating means defined by a blade pivotally secured on the pump shaft upstream of a screen located across the pump inlet. The blade either macerates large particles held on the screen until they are small enough to pass through the openings thereof, or if the particles are unmacerable, the blade bats the particles from the screen.
In U.S. Pat. No. 3,558,484, Wayne F. Carr shows a fiber separating apparatus having a screen arranged to pass only acceptable clean fibers and liquid. To insure against plugging of the openings of the screen, a plurality of stationary blades, or foils, are mounted to extend generally radially of and lie adjacent the inboard surface of the screen.
In U.S. Pat. No. 3,981,456 of Thomas M. Hahn et al, a food particle macerating means is shown including a cutting arm attached to a helically wound column. The cutting arm coacts with a gridlike grating element to macerate the food particles. The macerating device is arranged to move over or slip around unmacerable food particles, such as particles of bone, and serves to dislodge unmacerable particles from the grating element and urge them into a suitable associated trap.